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【DM版本】:
【操作系统】：
【CPU】:
【问题描述】*：
开发中遇到了一个mysql语句如下：
select
group_id AS groupId,
group_name AS groupName,
COUNT(IF(online_state = ‘0’,1,NULL)) AS unRegisterCount,
COUNT(IF(online_state = ‘1’,1,NULL)) AS onlineCount,
COUNT(IF(online_state = ‘2’,1,NULL)) AS offlineCount
from dmp_device GROUP BY group_id

我试着改为达梦的，如下：

select
group_id AS groupId,
group_name AS groupName,
COUNT(
CASE
WHEN online_state = ‘0’ THEN 1
ELSE NULL
END
) AS unRegisterCount
from dmp_device GROUP BY group_id​

但是报错，很苦恼，不知道怎么改，还请指点一下